This invention pertains to a process for the production of arylsulfonyl isocyanates having the formula EQU ArSO.sub.2 NCO
in which Ar designates phenyl, substituted phenyl, phenoxyphenyl, substituted phenoxyphenyl, thienyl, furyl, naphthyl, or substituted naphthyl.
Compounds of such type have been found useful as intermediates in the synthesis of arylsulfonyl-type herbicidal or plant growth regulant compounds, and hypoglycemic agents.
European Patent Application, Publication No. 44209, of E. I. DuPont de Nemours and Company, discloses production of a number of arylsulfonyl isocyanates as intermediates for herbicides and plant growth regulators, particularly at pages 12-18, 48, 51 and 69. Such methods include reaction of a sulfonamide with phosgene in the presence of an alkyl isocyanate in a solvent such as chlorobenzene, or reaction of a sulfonylurea with phosgene. The addition of a tertiary base to the reaction mixture may be advantageous. One such base mentioned in the European Patent Application, at page 15, is DABCO, or 1,4-diaza[2,2]bicyclooctane. Another method is the reaction of an arylsulfonamide with thionyl chloride to form an intermediate sulfinyl compound which is then reacted with phosgene in the presence of a pyridine catalyst to form the desired arylsulfonyl isocyanate.
European Patent Application Publication No. 64332, of E. I. duPont de Nemours and Company, discloses production of another series of substituted phenylsulfonyl isocyanates as herbicide intermediates, by similar methods. See particularly pp 8-10 and Examples 1, 2 and 6.